Carburetor



NOV- 2, 1965 J. L. SZWARGULSKI ETAL 3,215,413

JESSE L. SZWARGULSKI BY RALPH E. KALERT AGENT NOV- 2, 1955 J. L.szwARGULsKl ETAL 3,215,413

CARBURETOR 2 Sheets-Sheet 2 Filed Oct. 23. 1961 INVENToRs JESSE L.SZWARGULSKI RALPH E. KALERT AGENT United States Patent O 3,215,413CARBURETOR Jesse L. Szwargulski, Florissant, Mo., and Ralph E. Kalert,

Jr., Granite City, Ill., assignors to ACF Industries, Incorporated, NewYork, NX., a corporation of New Jersey Filed Oct. 23, 1961, Ser. No.146,896 3 Claims. (Cl. 261-41) This invention is directed to acarburetor for an internal combustion engine and particularly to novelstructures incorporating fuel circuits for such a carburetor.

An approach to cost reduction in the fabrication of a carburetor for aninternal combustion engine is in the use of a single casting to providethe several fuel circuits and the air-fuel mixture conduit for thecarburetor. One such design utilizes a single casting having a dependingportion to be enclosed within the fuel bowl of the carburetor andincludes the necessary fuel circuits provided by conduits and passagescast and drilled in the casting. The single casting also incorporatesthe air horn, the fuel -bowl cover, the mixture conduit and the throttlevalve support. In fabricating a carburetor in which cost reduction `isan essential goal, it is also possible to eliminate an excessive numberof levers and other parts which have been used in the past.

Accordingly, it is an object of this invention to provide a novelcarburetor which can be fabricated at a minimum expense and having aminimum number of parts.

It is another object of this invention to provide a novel carburetor foran internal combustion engine formed of a single casting in which thefuel circuits of the carburetor are easily formed with a minimum numberof parts.

It is another object of this invention to provide a novel carburetorstructure in which the carburetor consists essentially of a singlecasting and a fuel bowl and having a minimum number of working parts, inorder to reduce the cost of fabrication.

The invention is in a carburetor in which the object is to provide costreduction in its fabrication. For this purpose the carburetor isdesigned with all of its essential features incorporated in a singlebody casting. The body is provided with a depending portion enclosedwithin the fuel bowl of the carburetor. Attached to this dependingportion, which also forms the cover of the fuel bowl, there is formedthe main and idle fuel circuits, the accelerating fuel circuits, as wellas having supported therefrom the float and inlet valve for thecarburetor. The assemblage of parts is simplied so that the main fuelcircuit includes a fuel well having an adjustable jet which is varied bythe movement of a metering rod through the jet. lThe means foradjustably positioning the metering rod is a vacuum motor formed inalignment with the metering rod and attached directly thereto. A furthersimplification includes the utilization of the main fuel nozzle for thepassage therethrough of accelerating fuel upon the opening of thethrottle by manual operation. The idle system and main fuel system aredependent such that fuel ilow through the main fuel system maintains awashing action on the idle tube and thus prevents the forming of fuelvapors around the tube which would delay action of the idle circuit.Both the throttle and choke valves are mounted within the single castingas well as the operating levers for the a-ccelerating pump.

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The design of the carburetor is such as to provide a cornpact andreadily accessible carburetor to provide ease of replacement and repair.

FIGURE l is a plan view of a carburetor embodying the novel features ofthis invention.

FIGURE 2 is substantially a longitudinal sectional view of thecarburetor of FIGURE l, and shown mounted on an engine manifold with an-air filter partly in section.

FIGURE 3 is a partial sectional view of the carburetor of FIGURE l andalong section lines 3 3 of FIG- URE l.

FIGURE 4 is an enlarged sectional view of a portion of the structure ofFIGURE 3 illustrating further features of the invention.

FIGURE 5 is a sectional view of a portion of the carburetor of FIGURES land 2 illustrating schematically the idle circuit.

FIGURE 6 is a further sectional view Iof the carburetor and showing apart of the accelerating circuits of FIG- URES 1 and 2.

The carburetor shown in FIGURES 1 and 2 consists essentially of a singlecasting 10, which is formed with a fuel and air mixture conduit 12 and afuel bowl cover portion 14, from which is integrally formed a dependingstructure formed with an accelerating pump cylinder 16, an acceleratingfuel passage 18 yand a fuel well structure 2d. As shown, the mixtureconduit 12 is arranged and aligned vertically during operation and isconnected by a flange 13 to the intake manifold M of an internalcornbustion engine E. In the lower part of the conduit 12 there isrotatably mounted a throttle valve 22 fixed to a throttle shaft 24journaled in appropriately aligned apertures of the body casting 10. Inthe upper portion of the `fuel-air mixture Aconduit 12 there issimilarly mounted for rotational movement an unbalanced choke valve 26fixed to a choke valve shaft 28, which is also journaled in alignedapertures through the 'body casting 10. To the top of the mixtureconduit 12 is connected an air filter 29, partially shown in section inFIGURE 2. Between the upper and lower portions of the mixture conduit 12is formed a venturi or air flow restricting surface portion 30. A smallbooster venturi 32 is formed integrally with the body casting it) andhas an inner venturi surface 34 coaxially aligned with the mixtureconduit l12 and the primary venturi surface 30.

A plastic fuel bowl 36 is fixed beneath the fuel bowl cover 14 and isheld with its rim tightly against a gasket 38 fitted between the rim ofthe fuel lbowl 36 and matching portions of the fuel bowl cover 14. Afloat structure 40 Iis fixed to a float lever 41 which is pivotallymounted from pin 42 journaled in a depending portion of the fuel bowlcover portion 14. A lever arm 43 of the oat lever 41 abuts the lower endof a needle valve 44 having an upper tapered end extending into aresilient valve seat 46. Valve 44 and seat 46 control fuel flow into theinlet 47 to the fuel bowl 36. Inlet 47 is an integral part of casting10. A fitting may be threaded into inlet 47 to conne-ct the carburetorto a fuel line 48. Fuel is forced by a pump from a fuel tank 52 (bothschematically shown) through the fuel line 48 and into the carburetorinlet 47. With the fuel level in bowl 36 low, the float 40 is loweredand lever arm 43 allows valve 44 to be pressed -by fuel pressure and bygravity to an open position. Fuel flows into the bowl 36 `and when itreaches a predetermined level, the float lever 43 presses upwardlyagainst the needle valve 44 to close the inlet to the fuel bowl.

The lower end of the fuel well 20 is closed by a threaded fitting 56having a central orifice 69 therethrough (FIGURE 4), which is carefullyformed to provide a metering jet for the fiow of fuel from the fuel bowl36 to the mixture conduit 12. The upper end of the fuel well 20intercepts a cross fuel passage 58 drilled downwardly into the secondaryventuri structure 32. A nozzle fitting 60 is press-fitted into the endof passage 58 and has one end thereof extending into the Center of thesecondary venturi surface 34. Press-fitted within the Well 20 is a fuelemulsion tube 62 having apertures 63 therethrough along its length, asshown in FIGURE 4.

A metering pin 66 is suspended within the fuel well 20. Pin :66 has anend 68 formed with varying thicknesses. The formed end 68 is positionedwithin the main fuel jet orifice 69 for operation in response to enginerequirements. Flow of fuel through the main jet 56 is controlled by themetering rod 66 and in accordance with that portion of the formed end68, which is positioned within the jet 56, as described below. Themetering rod 66 is supported from a retainer 70 in which the upper endof rod 66 is frictionally engaged. The details of the retainer 70 androd 66 are the subject of a copending application of Jesse L.Szwargulski, Serial No. 131,175, filed on August 14, 1961, now PatentNo. 3,136,827.

A light spring 78 is positioned within a bore 77 between a shoulderportion 79 of the body casting 10 and the upper flanged end of theretainer 70. Spring 78 is of a strength to merely overcome the weight ofretainer 70 and the rod 66 and to thus always bias the upper surface ofretainer 70 against a diaphragm 80 which is sealed in an air tightmanner at its peripheral edge between a shoulder 81 of the body castingand a fitting 82 pressed into a matching bore 84 of the body casting.Diaphragm 80 extends across a cavity 86 which is formed from adepression in the bottom of bore 84 and fitting 82. On the upper side ofdiaphragm 80, opposite to the side against which the retainer 70 isbiased, is positioned a second retainer structure 88 similar inconstruction to retainer 70. A spring 90 is positioned between the topof a central bore 91 of fitting 82 and the lower flanged surface of theretainer 88 to bias the retainer 88 and diaphragm 80 in a downwardposition, as shown in FIGURES 2 and 4, for example. Bores 91 and 77 areaxially aligned but off to one side of the axis of the cylindrical well20. This suspends metering rod 66 to one side of the well axis andbiases the rod end 68 eccentrically within jet orifice 69 against theside of the jet fitting 56. This provides a consistent fiow of fuelthrough orifice 69 for any position of the metering rod 66.

The bore 91 is connected by a cross passage 92 to an annular passage 93formed in the peripheral surface of the fitting 82. As shown in FIGURE3, a passage 94 is formed through the body casting 10 to the flangeportion 13 of the carburetor and opens at 95 into the mixing conduit andmanifold M below or downstream of the throttle 22. In this manner,passage 94 connects the portion of cavity 86 above the diaphragm 80 tothe manifold pressure of the engine.

A passage 96 (FIGURE 2) is formed between the mixing conduit 12 from aregion between the choke valve 26 and the throttle valve 22 to extenddownwardly into the upper portion of well 20. Within the passage 96 ispressfitted a restriction element 98 for metering air fiow throughpassage 96 into the well 20.

As shown in FIGURE 4, a second well structure is Aformed from a bore 101in casting 10 to provide a second well` 103 adjacent to the well 20. Thebottom of Well 103 is partially closed by a fitting 105 having an axialpassage 107 therethrough of a predetermined cross section. Passage 107forms a fixed metering jet for the fiow of fuel from the fuel bowl 36upwardly into Well 103. A cross passage 109 connects well 103 withwe1l20. Flow 4 of fuel to the main nozzle is from the fuel bowl 36through both the fixed jet 107 and the adjustable jet 69 and the crosspassage 109 connecting the two fuel wells. Fuel then flows upwardlythrough the emulsion tube 62 into the main fuel passage 58 and out thenozzle 60.

For an engine of 195.6 cu. in. displacement, it was -urerp umurrurur eqlr/u Hem poialodo 69 ist gen1 puno; eter of 0.089. At the same time,the fixed jet 107 had a diameter of 0.03 8, while the metering rod end68 varied from a minimum diameter of 0.058 at 67 to 0.074" maximumdiameter. These values are examples only and are not limiting.

Mounted within the cylindrical recess 16 formed in body casting 10 is apump piston 100 (FIGURE 2), which is connected to a pump piston rod 102.A spring 104 is fitted between `the upper end of the pump cylinder 16and the piston 100. The lower end of the pump cylinder 16 is closed by afitting 106 having a central aperture 108 therethrough above which,biased by gravity, is a ball check valve 110. A fuel passage 112 extendsbetween the pump cylinder 16 and the cylindrical passage 18 formed inthe body casing 10. lPassage 112 permits fuel fiow into a fitting 114closing the lower end of cylindrical passage 18 and having at its upperend a valve seat in which the pointed end of a gravity biased checkvalve 116 is fitted. The cylindrical passage 18 extends upwardly andintercepts the main fuel passage 58, at which point a closure fitting118 is fixed. Fitting 118 forms an annular channel 117 with passage 58.Channel 117 is connected with a passage 119 formed axially throughfitting 118 and through which fuel can be ejected from the cylindricalpassage 18 into the main fuel passage 58 under pressure from the pumppiston 100. Passage 119 is formed off axis relative to passage 58 sothat the ejected fuel will not strike rod 66 and be directed into thewell 20. This is shown in FIGURE 4.

A low speed or idle circuit is provided in the carburetor and consistsof an idle tube 111 (FIGURE 4) pressfitted into the upper portion of thebore 101. The lower end of tube 111 is opened to receive fuel from Well103. The upper end of the tube is connected to a cross passage 113(FIGURE 5) which in turn is connected to a downwardly extending passageadjacent to the mixture conduit 12 of the carburetor. The passage 115 inturn extends into a chamber adjacent to the closed position of throttle22. An idle port 142 extends from chamber 140 to the mixture conduit 12and to both sides of throttle 22 in its fully closed position. A furtherpassage 121 extends downwardly from the chamber 140 to a second idleport 123 in the flange 13 of the casting 10. The idle port 123 opensinto the intake manifold M of the carburetor when the carburetor ismounted on the engine. The passage 121 forms an idle metering jet. Theflow of fuel and air therethrough is controlled by an adjustable idlescrew 125 threaded into an embossment 127 formed in the casting 10. Afixed metering restriction 129 is fittetd into the down passage 115 tocontrol the fiow of idle fuel through the passage. A further restriction131 is press-fitted into the upper end of passage 115, which also opensinto the mixing conduit 12 to provide a controlled supply of air intopassage 115.

As also shown in FIGURE 6, the annular channel 117 between fitting 118and the upper end of passage 58, is connected by a further passage 141to the air space 143 in the fuel bowl 36 above the level of the fuel inbowl 36. Air space 143 is formed in the upper end of the fuel bowl coversection 14 of casting 10. This space is connected to the air hornthrough a passage 145 (FIG- URE 5) formed in the fuel bowl cover section14 and into which a tubular fitting 147 is fixed extending into the airhorn section of the carburetor. Passage 145 and fitting 147 from aninternal vent for the fuel bowl and exposes the surface of the fuel inthe bowl 36 to the atmospheric pressure of air entering through the airfilter` 29 of the carburetor.

Within the passage 141, extending between the annular passage 117 andthe portion 143 of the fuel bowl cover, there is positioned a smallrestriction 148 to control the iiow of air from the fuel bowl into theannular passage 117. Passage 141 thus permits air to be bled into thepassages 119 and 18 of the accelerating circuit during normal operationof the carburetor when there is a low pressure present in the passage58. Without such an air bleed to provide a vacuum break, fuel would begradually forced out of the accelerating pump cylinder 16 and throughthe fuel passages 18 and 119 into the main fuel passage 58 during highspeed operation of the engine. Then, when accelerating is needed, thelack of fuel in the cylinder 16 will cause a stumbling effect -of theengine.

The operation of the structures described are as follows: Fuel from thefuel bowl 36 flows into both the pump cylinder 16 and the wellstructures 20 and 103 through openings 108, 69 and 107, respectively, tofill these recesses to the level of the fuel in the bowl. When theengine is running, air is sucked through the air filter 29 into themixture conduit 12 and the intake manifold M. The flow of air throughthe booster venturi 32 provides a sub-atmospheric pressure within theventuri surface 34 which extends back through the fuel passage 58 to theupper end of fuel well 20. The atmospheric pressure on the surface ofthe fuel within bowl 36 raises the fuel within the well andsimultaneously air is sucked through the restriction 98 and the bleedpassage 96 into the upper portion of the fuel well 20. This air passesaround and through the apertures 63 in the emulsion tube 62 to mix withthe fuel and its vapor and to form an air-fuel emulsion. The emulsion iscarried upwardly from the fuel well into the main fuel passage 58 andout the nozzle 60 to form a fuel and air mixture with the air passingthrough the mixture conduit 12. During engine operation fuel flows intothe bottom of well 20 through the fixed jet 105 and passage 109 and thevariable jet 56. Also, when the manifold pressure downstream of thethrottle 22 is less than the air pressure upstream of the throttle,additional fuel will be forced from well 103 through the idle tube 111and passages 113 and 115 and out the idle port 142. Air will bleedthrough restrictions 131 and 144 into passage 115 to form an emulsionwith the fuel .and to accelerate it through the ports 142 and 123.

At low engine speeds, the throttle 22 is partially closed so that themanifold vacuum in the intake manifold M below the throttle 22 isrelatively high. This vacuum is effective through the passage 94 uponthe upper surface of diaphragm 80 so that atmospheric pressure againstthe under surface of diaphragm 80 will press the diaphragm upwardly andpermit the metering rod and its retainer 70 to be carried with it in anupward direction. This brings the thicker portion of the metering rodend 68 into the main jet orifice 69 to cut down the flow of fuel throughthis orifice in accordance with the lower engine speed. As the throttle22 is opened progressively from low speed to high speed, the vacuumpressure in the manifold drops and permits spring 90 to bias thediaphragm 80 and the metering rod 66 downwardly until a thinner portionof the rod end 68 enters the jet orice to provide a greater iiow of fuelinto the mixing conduit 12.

The operation of the low speed idle circuit occurs when the throttle 22is operated in or near its closed position shown in FIGURE 5. At thisclosed throttle position, the manifold pressure below downstream ofthrottle 22 is very low, Iso that fuel is forced from the fuel well 103upwardly through idle tube 111, through passages 113, 115 and throughthe idle jet 121. Simultaneously air is sucked through the restriction131 to mix with the idle fuel and form an air fuel emulsion at thispoint. Additional air enters the idle chamber 140 through the restrictedpassage 144 between mixture conduit 12 and passage 115 and through thatportion of the idle port 142 which extends above the closed position ofthrottle 22. The amount of idle fuel and air mixture passing through theidle jet 121 and out the idle port 123 may be adjustably controlled bythe idle screw 125 having a tapered lower end which is moved in and outof the idle jet 121 to vary the ow of fuel and air through jet 121.

Additional air and fuel mixture is sucked from the chamber through theportion of idle port 142 below the throttle. As the throttle is slowlyopened, more and more of the idle port 142 is uncovered and exposed tothe manifold vacuum to provide a greater amount of air and fuel into theintake manifold to increase the speed of the engine. This also providesa smooth transition from low speed operation of the engine to theoperation of the engine at which the main fuel circuit takes over.During low speeds of engine operation, insufficient air flow passesthrough the venturi 32 of the mixture conduit 12 to draw fuel throughthe main nozzle 60. With the increase of fuel ow through idle port 142,engine speed increases t0 a point where air ow through venturi 32 beginsto draw fuel through the main nozzle 60.

The accelerating pump rod 102 is connected with a lost motion connection124 (FIGURES 1 and t2) by a linkage 126 to the throttle lever 128 whichis fixed for simultaneous movement with the throttle shaft 24. Throttlelever 128 has an arm 129 adapted to be connected to any means for manualoperation of the throttle 22. Any opening of the throttle by lever 12Swill allow spring 104 through the lost motion connection 124 to pressaccelerating pump piston 100 downwardly and force fuel out of the lowerportion of the pump cylinder 16 through passage 112 upwardly past thegravity biased valve 116 and into the annular portion 117 of the fitting118. This accelerating fuel under pressure will spurt out of the passage119 and will be directed into the nozzle structure 60 to provideadditional fuel for the increased air How due to the opening of thethrottle 22. This provides rapid response of the engine upon opening ofthe throttle.

The choke valve 26 is controlled during cold weather and during coldstarts by a thermostatic choke control device enclosed in a housingstructure 130. The choke control consists of a thermostatic coiledbimetallic spring 132 having one end fixed t0 a stationary stud 134mounted on the housing 130. The other end of the thermostatic springrests against one arm 136 of a lever fixed to the choke shaft 2S. Whenthe engine is cold, the thermostatic spring is tensioned in onedirection t0 press against the end of the lever 136 and rotate the chokeValve 26 toward a closed position. The iiow of air through the mixingconduit 12 at this point will partially open the unbalanced choke valve26 to permit sufficient air to pass on into the intake manifold M. Asthe engine heats up, the spring 132 relaxes and releases the end oflever 136 so that after a predetermined temperature has been reached thethermostatic coil 132 has no effect on the choke 26, which now willremain open by gravity, due to its unbalanced construction. The detailsof the choke are shown and described in the copending application ofJesse L. Szwargulski, Serial No. 140,371, filed September 25, 1961, nowPatent No. 3,133,977.

The carburetor structure described is one which provides the fabricationof a carburetor with cost reduction features. All portions of thecarburetor, except the fuel bowl, are formed from a single casting intowhich the passages and chambers are easily formed by well knownmachining and drilling. Several fuel circuits are cornpactly assembledin a depending portion of the carburetor which extends into the fuelbowl and is completely surrounded by fuel in the bowl during operation.This provides a cooling and insulating effect of these critical portionsof the carburetor by the fuel in the fuel bowl so that a minimum amountof ambient heat is absorbed by these carburetor parts. This minimizes avaporization of the fuel in the fuel passages and reduces the chances ofvapor lock during carburetor operation.

The metering rod 66, as described, is operated by the vacuum motorattached directly to the metering rod and which is directly aligned withthe metering rod. This'. eliminates connecting linkages and levers whichwould otherwise be necessary. Also, the metering rod 66 is. operativelydisposed within the emulsion tube 62 and forms a compact arrangement ofthese structures with thel emulsion tube passage directly intersectingthe main nozzle passage. Also, by feeding Athe accelerating fuel circuitdirectly into the main nozzle passage 58, a separate nozzleI structureand connecting passages are eliminated. The: accelerating pump cylinder16, as well as the passage 18,. and the well structures and 103 are allclosed at their bottom ends by press-fittings. However, as in the caseofthe fitting 56, shown in FIGURE 4, these fittings may' be threaded intothe ends of these passageways. Im either ease, however, the fittings areeasily accessible upon: removal of the fuel bowl and can be easilyreplaced or serviced if desirable.

The arrangement of the interconnected fuel wells 20 and 103, as shown inFIGURE 4, provides an advantage in that fuel passing through therestriction 107 is constantly flowing over the lower end of the idletube 111. This is true whether the fuel is passing through the passage109 into the main fuel well 20 and up the emulsion tube 62,' or whetherthe fuel'is passing upward through the idle tube 111 during low speedoperation of the engine. This constant fiow of fuel past the end of idletube 111 prevents the possible collection of fuel vapors around the endof the tube and the passage of such vapors up the idle tube 111 into theidle fuel passages. This tends to eliminate any tendency toward a vaporlock condition in the idle fuel passages.

We claim:

1. A carburetor for an internal combustion engine, said carburetorcomprising a fuel bowl and a body formed with an air and fuel mixtureconduit and adapted to be connected to the intake manifold of saidengine, said body formed with a fuel passage extending between said fuelbowl and said mixture conduit, a throttle mounted within said bodymixture conduit for movement from opened to closed poistion, said fuelpassage formed with first and second fuel wells within said body, afitting having a restricted orifice therethrough fixed to said body atthe lower end of said first fuel well and positioned within said fuelbowl, a metering rod movably mounted within said first fuel well, saidmetering rod having one end thereof positioned for movement through saidrestricted orifice, an emulsion tube depending from said body withinsaid first fuel well and having a lower free end thereof spaced from thewalls of said first fuel well and from the bottom of said first fuelwell, said emulsion tube surrounding said metering rod, means supportedby said body for moving said metering rod end within said orifice inresponse to engine operation, said body formed with a fixed jet passagebetween said fuel bowl and said second fuel well, an idle tube fixed tosaid body within said second well -and having a restricted endpositioned below the level of said emulsion tube and within the path offuel ffow from ,said fixed jet to said conduit, a conduit in said bodybetween said first and second fuel wells and positioned below the levelof the free end of said emulsion tube for fuel flow Abetween the firstand second fuel wells whereby fuel sive formation of Vvapor within saidsecond fuel well.

2. A carburetor for an internal combustion engine, said carburetorcomprising a fuel bowl and a body formed with an air and fuel mixtureconduit and adapted to be 7 connected to the intake lmanifold of saidengine, said body formed with a fuel passage extending between saidlfuel bowl and said mixture conduit, a throttle mounted Within said bodymixture conduit for movement from opened to closed position, said fuelpassage formed with first and second fuel wells Within said body, afitting having a restricted orifice therethrough fixed to said body atthe lower end of said first fuel well and positioned within .said fuelbowl, a metering rod movably mounted within ,said first fuel well, saidmetering rod having one end thereof positioned'for movement through saidrestricted orifice, an emulsion tube depending from said body withinsaid first fuel Well and having a lower free end thereof spaced from thewalls and from the bottom of said first fuel well and surrounding saidmetering rod, said body formed with a fixed jet passage between saidfuel bowl vand said second fuel well, a conduit formed in said body'between said first and second fuel wells and being positioned below thelevel of the free end of said emulsion tube, an idle tube fixed to saidbody within said second well and having a restricted end positionedbelow the level of the free end of said emulsion tube and in alignmentwith said fixed jet and with said conduit, whereby fuel flowing throughsaid fixed jet to said conduit will sweep the restricted end of theemulsion tube to cool the same and to prevent the formation of excessivefuel vapor.

3. A carburetor for an internal combustion engine, said carburetorcomprising a fuel bowl and a body formed with an air and fuel mixtureconduit and adapted to be connected to the intake manifold of saidengine, said body lformed with a fuel passage extending between saidfuel bowl and said mixture conduit, a throttle mounted within :said bodymixture conduit for movement from opened to closed position, said fuelpassage formed with first and second fuel wells within said body, afitting having a restricted orifice therethrough fixed to said body atthe lower end of said first fuel well and positioned within said fuelbowl, a metering rod movably mounted within said first fuel well, saidmetering rod having one end thereof positioned for movement through saidrestricted prifice, an emulsion tube depending from said body with- 1nsaid first well and having a lower free end thereof spaced from thewalls and from the bottom of said first fuel well, said emulsion tubesurrounding said metering rod, said body formed with a fixed jet passagebetween said fuel bowl and said second fuel well, an idle tube fixed tosaid body within said second well and having a restricted end positionedbelow the level of the free end of said emulsion tube and within thepath of fuel flow from said fixed jet to said conduit, a conduit formedin said body between said first and second fuel wells and beingpositioned adjacent the level of the free end of said emulsion tube andaligned horizontally with the restricted end of said idle tube, wherebyfuel flowing through said fixed jet passage, and through said conduit tothe first fuel well will sweep the restricted end of said idle tube tokeep the same cool and to prevent the formation of vapor in said secondfuel well.

References Cited by the Examiner UNITED STATES PATENTS 2,660,417 ll/53Anderson 261-34 2,771,282 ll/56 Olson et al. 261-41 2,877,996 3/59Kinney et al 261-34 2,882,028 4/59 Seldon 261-72 2,914,307 11/ 59Eickmann 261-69 X 3,031,172 4/62 Rapplean 261-72 X 3,076,639 2/63Szwargulski et al 261-34 3,136,827 6/ 64 Szwargulski 261-72 X 0 HARRY B.THORNTON, Primary Examiner.

HERBERT L. MARTIN, Examiner.

1. A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE, SAID CARBURETORCOMPRISING A FUEL BOWL AND A BODY FORMED WITH AN AIR AND FUEL MIXTURECONDUIT AND ADAPTED TO BE CONNECTED TO THE INTAKE MANIFOLD OF SAIDENGINE, SAID BODY FORMED WITH A FUEL PASSAGE EXTENDING BETWEEN SAID FUELBOWL AND SAID MIXTURE CONDUIT, A THROTTLE MOUNTED WITHIN SAID BODYMIXTURE CONDUIT FOR MOVEMENT FROM OPENED TO CLOSED POSITION, SAID FUELPASSAGE FORMED WITH FIRST AND SECOND FUEL WELLS WITHIN SAID BODY, AFITTING HAVING A RESTRICTED ORIFICE THERETHROUGH FIXED TO SAID BODY ATTHE LOWER END OF SAID FIRST FUEL WELL AND POSITIONED WITHIN SAID FUELBOWL, A METERING ROD MOVABLY MOUNTED WITHIN SAID FIRST FUEL WELL, SAIDMETERING ROD HAVING ONE END THEREOF POSITIONED FOR MOVEMENT THROUGH SAIDRESTRICTED ORIFICE, AN EMULSION TUBE DEPENDING FROM SAID BODY WITHINSAID FIRST FUEL WELL AND HAVING A LOWER FREE END THEREOF SPACED FROM THEWALLS OF SAID FIRST FUEL WELL AND FROM THE BOTTOM OF SAID FIRST FUELWELL, SAID EMULSION TUBE SURROUNDING SID METERING ROD, MEANS SUPPORTEDBY SAID BODY FOR MOVING SAID METERING ROD END WITHIN SAID ORIFICE INRESPONSE TO